Chapter 1

An INVENTORY is a list of terms and assumptions used to prove that our observations about geometric behavior hold true.

As we go along, our inventory will be refined to be as clear as possible. As we prove, disprove, and salvage our observations about geometric behavior, we will maintain a list of those theorems. This is called a deductive system in mathematics.

We will always strive to be thoughtful of the language we use in our definitions. Clarity and brevity is important.

Let's consider the term "line segment". Take a moment right now to write down a definition for "line segment".